JPH028547A - Method of controlling regulating pressure in automatic transmission - Google Patents

Abstract

PURPOSE: To minimize the requisite memory capacity and reduce the circuit cost by storing the digital reference value of a hydraulic adjust current to control the adjusting pressure of an automatic transmission in a memory place with an address based on two engine parameters. CONSTITUTION: A microprocessor makes AD conversion of an accelerator pedal position signal, and the resultant value is stored in a register R6' as a load value and fed to a cumulator A to undergo a one-digit left shifting so that the lower five digits are erased. To any empty digit in the cumulator A, the engine speed is read from a counting register R1 and read into a register R4' as a lower table value. An inquiry is made for which characteristic region to be applied, and an upper table value obtained by 20H heightening the lower table value R4' in the applicable region is read into the cumulator A, and a hydraulic adjust current is set through 16 runs of interpolating calculation. Thereby the requisite memory capacity is lessened and the circuit configuration is simplified, and the adjusting pressure can be controlled accurately and finely.

Description

DETAILED DESCRIPTION OF THE INVENTION Industrial Application The invention starts from a method for controlling the regulation pressure in an automatic transmission of a vehicle, as defined in the preamble of claim 1.

Problems to be Solved by the Prior Art and the Invention The regulating pressure forms a hydraulic pressure and therefore controls the entire thread bobbin in an automatic transmission. The regulating pressure controls the hydraulic valves that set the speed stages of the automatic transmission.

Known automatic transmissions use engine load and engine speed as parameters. At that time, the load is determined by the accelerator pedal position, and the rotation speed is determined by the centrifugal force regulator.
In other words, it is determined mechanically. These parameters are used to set the regulating pressure and thereby the instantaneous desired speed stage. The method of controlling the regulated pressure has the disadvantage that it is imprecise, has a large number of mechanical components, and is therefore susceptible to interference.

It is also known to control solenoid valves that influence the regulating pressure using an electronic control device having one or more characteristic areas. Here too, the rotational speed and the load can be used as parameters for setting the regulating pressure. In order to realize precise setting of speed stages, a large number of values must be stored in the characteristic area. It has also been proposed to use three-dimensional characteristic regions to control the regulating pressure. Both types of solenoid valve control methods are very complicated and expensive, especially when fine speed changes are required. The large storage requirements of these control methods are also extremely disadvantageous.

Measures for solving the problem and effects of the invention In contrast, the method according to the invention as defined in the characterizing part of claim 1 provides a method which requires only a small amount of storage and has a reduced circuit cost, while still allowing for adjustment. A very precise and delicate control of the pressure is achieved, which has the advantage of very high switching characteristics.

16 times when assigning two engine parameters, namely the value of the load and the rotational speed, as a combined value to the address of the memory cell of the characteristic area, and recalling the value of the desired characteristic area assigned to the address of the memory location. It is particularly advantageous if interpolation is performed. In this way, a large number of values can be retrieved from the characteristic range for controlling the regulating pressure without increasing the storage space requirements.

Embodiments Next, the present invention will be explained in detail with reference to the drawings, with reference to the illustrated embodiments.

The key idea of the method of the invention is that the regulating pressure in the automatic transmission of a vehicle is controlled in such a way that a very fine control of the gear changes is possible, depending on the load or engine torque and rotational speed. That's true. As already mentioned, the more data there is for controlling the regulated pressure, the more precisely the speed stage changes can be controlled. However, the larger the number of control data, the larger the required storage space. In the method according to the invention, the storage space is reduced by combining the determined values of load and rotational speed with each other and assigning the result to the address of a storage location in the respective characteristic field. The required storage space can be further reduced if a special evaluation method is adopted when determining the rotational value.

Regulating pressure is generated by a pressure regulator.

The pressure regulator converts the supplied electrical current into a proportional pressure.

In this case, the regulating current does not flow continuously. A digital reference is provided in advance to the hybridized regulation circuit as a pulse on/off ratio. Starting from a maximum 1A regulation current, for example if a regulation current of 840 mA is desired, the pulse on-off ratio is set to 84%.

The pulse on/off ratio depends both on the instantaneous rotational speed n and on the instantaneous load. The values of the pulse on-off ratio required for a given operating state are read out from the matrix shown in FIG. 3, which has 32 columns for rotational speed n and 8 rows for negative IP. Therefore, here, 25
6 different values are available. In order to be able to match the regulating current and thus the speed gear as precisely as possible to the current conditions, 16 interpolations are carried out between two line values or between two load values. Based on interpolation, 4096 different values for the regulation current are calculated. This allows a very fine setting of the regulating pressure to be achieved even with a relatively small storage space requirement.

Below, 32 columns for rotational speed and 8 for load
The creation of the matrix shown in FIG. 3 by determining the two rows will now be described in detail.

First, a description will be given of how the rotational speed n is determined based on the method shown in FIG.

e.g. 1 by an internal combustion engine connected to an automatic transmission.
A gear wheel with 60 teeth moves.

The number of teeth moving past the sensor within a predetermined time, ie a reference time or gate time, is detected and stored. In parallel with the rotation speed measurement, the digital standard is 15-
Output to a hybridized regulation circuit for 6x pulse on-off times of 657m5. The sum of the numbers of teeth determined at this time is stored in a so-called rotational speed register R5.

In this case, the counting operation is carried out by an electronic control, for example a microprocessor, which is also provided for supplying a digital reference corresponding to the regulating current of the regulator. The microprocessor is configured to simultaneously determine the regulating current of the hydraulic regulator while it counts the teeth of the gearwheel, with a pulse on/off ratio corresponding to the rotational speed and load of the preceding measuring process. is set. In the method of this embodiment, the sum of the pulse on duration and the pulse off duration is always constant. The rotational speed is measured over the period of delivery of six consecutive pulses.

Before the rotation speed measurement or the start of the counting operation, in a first step the memory cell TFlag is used as the forward counting register R1 timer TIM and timer 7 lag.
is sected to zero.

Then the counter CNT starts (STRTCNT)
In a second step, a reference pulse of the regulating current is switched on. While the pulse is connected, the counter CN
T counts the number of teeth on the gear. That is, the output signals of a sensor arranged on the gear wheel are detected and the output signals corresponding to the teeth passing the sensor of the gear wheel are counted.

The input connection time of the reference pulse is controlled by the first register R3 to which the initial value is input from the sub-register R23. Below, based on the flowchart of FIG. 5, a detailed explanation will be given of how the values input to the sub-registers are obtained. Register R3 counts backwards to zero. If, in the interrogation in the fourth step, it is detected that the register R3 has counted from its initial value to 0, the reference pulse is cut off.

The time interval during which the reference pulse is interrupted is controlled by another register R4 with backward counting. The starting value of this register is taken from subregister R24. The value stored in subregister R24 corresponds to the value of the complement of the contents of subregister R23. In the interrogation in the fourth method step, when it is detected that register R4 has completed the backward counting state from the initial value to the value O, the value of forward counting register R1 is increased by one.

Finally, in the eighth step, it is determined whether the counting register R1 takes the value 6, so that the counting process totals 6
It is checked whether the number of times has elapsed. in that case,
The current state of the counter CNT is input as a rotational speed storage value to a register R5 called a rotational speed register.

The pulse on/off ratio for the six counting cycles is therefore set by registers R3 and R4, the starting value for the register counting in the opposite direction being taken from the subregister. The purpose of the setting is to ensure that during the speed measurement process the regulator of the automatic transmission is supplied with a regulating current that is matched to the instantaneous speed and load.

In the 10th step, it is detected whether an overflow of the count 6CNT has occurred using a timer flag or a counter flag. The set memory cell F1 remains unchanged and maintains its state. However, when the counter overflows, that is, there is a false measurement, set Fl to 1! - Return to the main program later.

Therefore, based on the value of Fl, it is detected whether the rotational speed measurement was carried out without error.

However, it is not only an error check whether the predetermined maximum value of the rotational speed register R5 is exceeded. Since the minimum rotation speed of the engine cannot be lower than 400 rpm, the minimum count state of the rotation speed register R5, which cannot fall below, is also determined. If, at the end of the measuring cycle, the current counter state is lower than the minimum counter state corresponding to the minimum rotational speed, an erroneous measurement of the rotational speed has also occurred in this case.

Such error monitoring will now be explained based on the flowchart of FIG.

Using the method illustrated in FIG. 1, after the current rotational speed indication method has completed, the main program is returned and the counting state N of the rotational speed register R5 is formed from n.

If the measurement time is MZ = 15.657 ms, the number of gear teeth is 160, and the gear rotation time is T, then
The following formula holds true for the counting state N of the counter CNT and U: =0.04 1752 ・ n [min-1
]-0,015657・f [Hz] From this formula,
The value of the counting state of R5 is the minimum N-1 for 40 Orpm.
7 and N-116 for 2707 rpm. There are therefore 100 different counts for N. If we were to allocate a unique storage location to every value, we would need 100 storage locations. The larger the rotational speed measurement area, the larger the required storage space.

FIG. 2 illustrates how the storage requirements are reduced to 32 storage locations.

Also in the flowchart of FIG. 2, R1 indicates a positive direction counting register. This register takes the value O as the minimum value and the value 31 to 1 in lO decimal as the maximum value.
It is possible to take an IF in hexadecimal representation.

In the first step the counting register R1 is set to zero. Subsequently, a check is made as to whether the minimum possible value of the counting state of rotational speed register R5 has fallen below. If this is the case, i.e. when the content of the rotational speed register R5 does not correspond to the actual rotational value, the value conversion of the predetermined value of R5 is interrupted, the counting register R1 is again set to zero and the rotational speed register Value conversion of the next value of R5 begins. When the contents of the rotation speed register R5 are greater than 17,
In a third step the minimum value is subtracted from the value of the counting state and the result is stored in accumulator A. In the next step the complement of the accumulator contents is formed.

In a subsequent fifth step, it is checked whether an over 70- or CarryC occurs when the fixed value denoted datal is added to the current contents of the accumulator, here as datal. value 3
is selected. Addition is performed a maximum of 32 times. Over 7
0-, it is detected in the next test step whether the counting state of the forward counting register R1 exceeds the maximum value 3 to IFH. If this is not the case, the instantaneous value of the counting register R1 is made to correspond to the entered rotational speed storage value and subsequently the next rotational speed storage value of the rotational speed register R5 is converted.

If the instantaneous stored value of forward counter R1 is greater than 31 to IFH, counter R1 is set to 31 and this value is made to correspond to the value-converted rotational speed stored value in R5. Subsequently, the next rotational speed stored value is converted into a value.

In the fifth step, the accumulator contents and the fixed value datal
If no overflow occurs during the addition to the accumulator contents, the contents of the counting register R1 are increased by one step and it is checked again whether an overflow has occurred after the next addition of the value datal to the accumulator contents.

In short, using the method shown in Figure 1, here the speed is 400 rpm.
and 2707 rpm, 17 and 11
It can be seen that the rotational speed memory value stored in the rotational speed memo IJR between 6 and 6 is made to correspond. In this way, various rotational values of 2308 are changed to 100 in this method.
is assigned to a storage location.

In the subsequent step illustrated in FIG. 2, 32 memory locations are allocated to the 100 memory locations. At that time, the value of the rotation speed register R5 is set to the positive direction counting register R.
FIGS. 3a and 3b, with corresponding values of 1, show characteristic fields or matrices in which the rotational speed n is plotted in the horizontal direction. In this case, 32 steps or memory locations are assigned to the rotational speed range from 400 to 2707 rpm. These stages correspond to the storage locations of the counting register R1.

In the vertical direction, the load P is shown, with 0% and 1
There are 8 stages between 00% and 00%.

Therefore, in each step the value of the load is increased by 12.5%.

Overall, therefore, a matrix is shown in FIGS. 3a and 3b with 32 columns for rotational speed n and 8 rows for load P.

The individual areas or storage locations of the matrix are numbered line by line, with serial numbers in hexadecimal notation being indicated.

In the following it will be explained how the individual values of the memory locations of the matrix are determined and evaluated.

FIG. 4 shows how the values obtained for the instantaneous load are compared with the values for the rotational speed obtained by the method illustrated in FIGS. 1 and 2 in order to determine the address of the memory location of the matrix. The diagram shows how they are combined.

In order to detect the instantaneous load on the internal combustion engine, the regulating rod stroke, ie the accelerator pedal position, is evaluated; a large regulating rod stroke occurs when more gas is supplied. The adjustment rod travel is conventionally measured and an analog signal is therefore generated, which is applied to an AD converter. The output signal of this converter is a binary value of up to 7 digits, ie its value lies between 0 and 127. In the first step, as shown in FIG. 4, the output signal of the AD converter is stored as a load value in register R6'. This value is input to accumulator A.

In the second step the load value is shifted one place to the left, ie multiplied by two. Then the bottom 5 of the accumulator
The digit is deleted.

The rotation value is read from the count register R1 into the empty digit of the accumulator. The storage value obtained in this way corresponds to the address of the storage cell, which is read into register R4' and assigned to the "lower table value".

In the next fourth step, an inquiry is made as to which table or matrix is to be used.

It is therefore possible to apply this method to a plurality of characteristic areas formed for each type of engine. In FIG. 4, for example, table values from the first matrix or table 1 are read into accumulator A. table 1
The table value at corresponds to the memory location address stored in register R4'. In the case of another engine, the lower table value R4' is read into the accumulator from another matrix in the fifth step of FIG. In that case, this table value would be suitable for another institution.

After the lower table value has been loaded into accumulator A, this value is transferred to register R2' in a seventh step. Subsequently, in an eighth step, the memory location address stored in register R4' is increased by 20H and this value is read into accumulator A and made to correspond to the upper table value. It is clear from FIGS. 3a and 3b that by adding the values 20H in the same column, the values of the storage cells are read out as the next higher row and transferred to the accumulator. Before this value of the storage cell is read out, it is checked in which matrix or characteristic area the associated value is to be searched for in the next query. In the last, twelfth step, the value read from the matrix or characteristic field, which corresponds to the upper table value, is stored from the accumulator in the register R1' as the upper table value.

It is clear from FIGS. 3a and 3b that the value field is divided into 256 steps and that they are stored in the associated matrix field. 1 using the method shown in Figure 4.
The upper and lower table values within one column are read from the matrix. Therefore, 16 interpolations are performed, which will be explained in detail with reference to FIG.

According to the method shown in FIG. 4, the upper table value is in register R.
1' and the lower table value is in register R2'.

In a first step the difference between the upper table value and the lower table value is formed. If in the second step it is detected that the result is negative, this difference value is divided by 2 and the result is entered in the register R3' in the third step. The result of the subsequent division by 2 is stored in register R4'.

In the fifth and sixth steps the next division by 2 is carried out, the result being placed in registers R5' and R7.
' will be remembered. Finally, in a seventh step, the load value determined on the basis of the adjustment rod stroke and stored in register R6' is input to accumulator A. Based on the explanation of flowcharts 1-- of FIG. 4, it is determined that only the three most significant digits of the determined load value are used so far. The remaining digits are then used for interpolation. Therefore, the load value input to accumulator A is OF (and A, N
D is added. The resulting value is input into register R1'. Finally, in the same step, register RO'
is set to zero.

In the eighth step, it is subsequently checked whether the value in register R1' is greater than or equal to eight. Otherwise, it is subsequently checked whether the value of R1' is greater than or equal to 4. If this value is less than 4, then this value continues to be greater than 2 or
is checked for equality. Subsequently, in an eleventh step, it is checked whether the formula RM=1 holds true when the value of RM is less than 2. If this formula is not satisfied, the contents of register RO' are added to register R2' containing the lower table value.

In the following thirteenth step, it is checked whether an overflow occurred during the previous addition. Otherwise, the value resulting during the addition is subregister R
The complement of the value input to R23 and obtained during addition is stored in subregister R24. If an overflow occurs during addition, a fixed value data2 is input to sub-register R23.

Based on the flowchart in FIG. 1, sub-register R23
As already mentioned, the values present in R24 and R24 are used to set the desired pulse on/off criteria for the regulated current. It is therefore clear from the description of FIG. 5 that the value obtained on the basis of interpolation determines the pulse injection duration. Its complement value in sub-register R24 is evaluated to set the pulse on-off ratio. In order to ensure that the transmission is not damaged in the event of a fault, the 13th step of the interpolation explained in FIG. A high regulation pressure in the transmission is set.

If a negative result occurs when subtracting the lower table value from the upper table value, the accumulator contents are set to zero in a fifteenth step before the start of interpolation. This prevents interpolation from being carried out with incorrect starting values.

In the test in the eighth step, register R1'
If it is clear that the value in is greater than or equal to 8, then in the sixteenth step
A certain value is added to R3' and the contents of register R1' are reduced by eight. The value then produced is again stored in register R1'.

In the test performed in the ninth step, R
If it is clear that the stored content of 1' is greater than or equal to 4, an addition of the values present in the memory RO' and the memory IJ R4' is carried out in an eighteenth method step. Subsequently, the storage contents of R1' are reduced by 4, and the result generated here is also stored in memory R1'.

If, during the test in the tenth step, it is clear that the stored content of R1' is greater than or equal to 2, then in the seventeenth step the values present in the memories RO' and R5' are added; The memory content of R1' is 2
, and the resulting result is again the memory R
1'.

In the final inspection conducted at the 11th step,
If it is detected that the stored contents of R1' have the value 1, the contents of register R7' are added to the contents of register RO' in a nineteenth step.

The relationship between the control parameters rotation speed, load, and adjustment pressure will be explained once again based on FIG.

To this end, FIG. 6 shows the characteristic curve area obtained during a test run of the internal combustion engine on a test bench. In the horizontal direction, the rotational speed n is shown, and in the vertical direction, the torque, the regulating pressure and the regulating current of the internal combustion engine are shown. The curves are shown for different adjusting rod travels X. For the top curve in FIG. 6, the maximum torque at the maximum adjustment rod stroke then occurs. Within the family of curves, the torque decreases from top to bottom. At the same time, each adjustment rod curve is decreasing. At high torques, high regulating pressures must be built up in order to enter the appropriate speed gears. In this case, the regulating current required for controlling the solenoid valve increases from curve to curve and from top to bottom. At the same time, it can be seen that the regulating current increases from left to right in the course of the curve in the characteristic region up to a medium rotational speed and then decreases again.

Variables and L are shown in the curves for clarity of presentation. From bottom to top, the group curves show values of =O to -10 for the variables. At the same time the 6th
Vertical dashed lines are shown in the figure. The spacing between these vertical lines is all the same. They are given variable values L=0 to L=10 from left to right. The vertical line shown as K and the curved line K give rise to individual regions whose position is determined by the intersection of the straight line and the curved line.

Below, it is determined by the following intersection points, namely L-4
, -4; L-5, -4: L-4 -5; L = 5. An explanation will be given by taking up the individual area determined by -5. The areas resulting from these intersections are highlighted by hatching.

Since it is not possible to calculate or specify the associated values for all points in the characteristic curve area, during the test run on the test bench the speeds, torques, adjusting rod values and A measurement of the regulated current is performed. In this way, the rotational speed, pressure, regulating rod value and regulator current for the corner points of the hatched area are determined. Interpolation of speed and torque is carried out when intermediate values within the range are required for regulating the regulating pressure.

From what has already been said, it is clear that the adjustment current required to generate the optimal adjustment pressure can be determined from a group of curves according to the determined rotational speed and torque. Using known data processing programs, it is possible to determine in each case the regulating current associated with a given rotational speed and a given torque and to transfer the associated values to the matrix shown in FIG. 3, which consists of 32 columns and 8 rows. can. The regulation current is pre-loaded to a hybridized regulation control circuit by a digital reference pulse on-off ratio stored in the matrix.

It is now clear that the values of the regulating current required for controlling the regulating pressure can be read out from the matrix described above and at the same time from the characteristic range shown in FIG. It has also been shown from the foregoing that, despite the relatively small storage requirements, the described interpolation method makes it possible to generate a large number of intermediate values, so that the speed range of the automatic transmission can be changed in each case to a very large number. It is easy to see that it is possible to precisely match given conditions.

[Brief explanation of the drawing]

FIG. 1 is a flowchart showing a rotation speed measurement method in which a value corresponding to the rotation speed is stored in a rotation speed register;
2 is an illustration of a flowchart illustrating a method for reducing the storage space required for storing rotational speed, and FIGS. 3a and 3b show columns corresponding to 32 different rotational speed ranges and 8 different FIG. 4 is a flowchart showing a method for selecting an upper table value and a lower table value from the characteristic area; FIG. The figure shows the value of the characteristic area as 16
FIG. 6 is an illustration of a 70-chart illustrating a method for interpolation, and FIG. 6 is a diagram illustrating a characteristic curve area obtained on an engine inspection bench. R1... Counting register, R5... Rotation speed register A
...Accumulator, P...Load, n...Rotation speed -〇 0L=1 2 2 3 L=4 5 6 7 L=8 9 L=10

Claims (1)

[Claims] 1. A method for controlling regulating pressure in an automatic transmission using an engine data characteristic area, characterized in that a digital reference value of a hydraulic regulating current is input into a memory location having an address determined from two engine parameters. Method of controlling adjustment pressure in automatic transmission.